These [following] are the heads of the fathers’ houses: Since [Scripture] had to trace the lineage of the tribe of Levi as far as Moses and Aaron-because of Moses and Aaron-it commenced to trace their [the Israelites’] lineage in the order of their births, starting with Reuben. (In the Great Pesikta [Rabbathi] (7:7) I saw [the following statement]: Because Jacob rebuked [the progenitors of] these three tribes at the time of his death (Gen. 49:4-7), Scripture again traces their lineage here by themselves, to infer that [even though Jacob rebuked them] they are of high esteem.)

and the years of Levi’s life: Why were Levi’s years counted? To let us know how many were the years of bondage. For as long as one of the tribes was alive, there was no bondage, as it is said: “Now Joseph died, as well as all his brothers,” and afterwards, “A new king arose” (Exod. 1:6, 8), and Levi outlived them all. — [from Seder Olam, ch. 3]

And the years of Kehath's life and the years of Amram's life etc: From this calculation we learn that the 400 year sojourn of the B'nei Yisrael which Scriptures talks about, it was not [spent] in Egypt alone but, rather [was calculated] from the day Yitzchok was born. [This can be calculated thus:] For Kehath was among those who went down to Egypt, [Now] calculate all his years and the years of Amram, [his son] and the eighty years of Moshe, you will find that they do not total 400 years, many of the [sons'] years are included in the fathers' years

25Eleazar, the son of Aaron, took himself [one] of the daughters of Putiel to himself as a wife, and she bore him Phinehas; these are the heads of the fathers' [houses] of the Levites according to their families.

[one] of the daughters of Putiel-: Of the seed of Jethro, who fattened (פִּטֵּ ם) calves for idolatry (see Rashi on Exod. 2:16) and [who was also] of the seed of Joseph, who defied and fought (פִּטְפֵּט) against his passion [when he was tempted by Potiphar’s wife]. — [from B.B. 109b]

That is Aaron and Moses: Who are mentioned above [verse 20], whom Jochebed bore to Amram, [these two] are [the same] Aaron and Moses to whom the Lord said, etc. In some places, [Scripture] places Aaron before Moses, and in other places it places Moses before Aaron, to tell us that they were equal. — [from Mechilta, 7:1]

with their legions: Heb. ע ַל-צִבְאֹתָם [equivalent to בְּ צִ בְאֹתָם], with their legions. [I.e.,] all their legions according to their tribes. There are [examples] of עַל when it is used instead of one letter, [e.g.,] “you shall live by your sword (עַל-חַרְבְּ) ” (Gen. 27:40), [which is] the same as בְּחַרְבְּ [by your own sword]; You stood by your sword (עַל-חַרְבְּכֶם) (Ezek. 33:26), [which is the same as] בְּחַרְבְּכֶם